饮水硼暴露对固始鸡血细胞的影响

目的研究饮水添加不同水平硼对固始鸡血细胞的影响,为硼在人类和动物营养方面的正确使用提供科学依据。方法将1日龄240羽清洁级固始鸡随机分为对照组和硼100、200、400 mg/L染毒组,每组60羽。染毒组以饮水添加硼酸形式补硼,对照组饮用自来水,染毒6周。观察并记录染毒过程中鸡的采食、饮水、活动和临床症状,每周称重1次。每周末测定各组红、白细胞数及血红蛋白含量,白细胞分类计数,观察血细胞形态结构变化特点并显微摄影。结果与对照组比较,100mg/L染硼组固始鸡的临床症状和剖检无明显变化;第1～3周平均体重,第2周红细胞数,第4周红、白细胞数,第3、6周嗜碱性粒细胞比例,第1、4、6周淋巴细胞比例和第4周单核细胞比例均低于对照组,且差异有统计学意义(P<0.05或P<0.01);第1～3周各种血细胞形态结构受到轻微损伤。高剂量染硼组(硼添加量≥200mg/L),固始鸡的临床症状和剖检变化随硼添加剂量增大而趋于明显;各周体重,红、白细胞数和血红蛋白含量均降低,部分指标差异有统计学意义(P<0.05或P<0.01);各种白细胞比例变化较明显,其中淋巴细胞和嗜碱性粒细胞比例与对照组比较,部分指标有统计学意义(P<0.0...     

Effects of aflatoxin B(1) and fumonisin B(1) on blood biochemical parameters in broilers

The individual and combined effects of dietary aflatoxin B(1 )(AFB(1)) and fumonisin B(1) (FB(1)) on liver pathology, serum levels of aspartate amino-transferase (AST) and plasma total protein (TP) of broilers were evaluated from 8 to 41 days of age. Dietary treatments included a 3 × 3 factorial arrangement with three levels of AFB(1 )(0, 50 and 200 μg AFB(1)/kg), and three levels of FB(1 )(0, 50 and 200 mg FB(1)/kg). At 33 days post feeding, with the exception of birds fed 50 mg FB(1 )only, concentrations of AST were higher (p < 0.05) in all other treatment groups when compared with controls. Plasma TP was lower (p < 0.05) at six days post feeding in groups fed 200 μg AFB(1)/kg alone or in combination with FB(1). At day 33 days post feeding, with the exception of birds fed the highest combination of AFB(1 )and FB(1 )which had higher plasma TP than control birds(, )plasma TP of birds fed other dietary treatments were similar to controls. Broilers receiving the highest levels of AFB(1) and FB(1) had bile duct proliferation and trabecular disorder in liver samples. AFB(1) singly or in combination with FB at the levels studied, caused liver damage and an increase in serum levels of AST.     

外源核苷酸对肉鸡生产性能的影响

研究了天然日粮中补充外源核苷酸对肉仔鸡胃肠道等消化器官及生产性能的影响 .0～ 14日龄爱维因肉仔鸡按体重随机分成 4组 ,每组 4个重复 ,分别饲喂玉米豆饼无鱼粉基础日粮 ( 1组 ) ,基础日粮中添加 0 .0 5%核酸 ( 2组 )、0 .1%核酸 ( 3组 )以及基础日粮中含 2 %鱼粉 ( 4组 ) .结果表明 ,第 2 ,3,4组的肉仔鸡 14日龄生长速度比对照组提高 14%～ 17% ,饲料利用率提高 4 %～6% .2、3组鸡 4日龄十二指肠质量、3组鸡空肠质量、胰腺质量显著高于对照组 (P <0 .0 5) ;7日龄小肠粘膜的蛋白酶活性也极显著高于对照组 (P <0 .0 1) .研究表明 ,日粮中添加外源核苷酸对提高肉仔鸡生长速度、胃肠道、胰脏质量、肠粘膜蛋白酶活性均有重要的影响 .     

The First Report of a Virulent Newcastle Disease Virus of Genotype VII.2 Causing Outbreaks in Chickens in Bangladesh

Newcastle disease (ND) is endemic in poultry in Bangladesh. We performed genotypic and pathotypic characterization of four ND virus (NDV) isolates from recent outbreaks in broiler chickens in Bangladesh during the period of 2020–2021. Phylogenetic analysis based on the complete fusion protein gene coding sequences classified the viruses into NDV class II genotype VII.2 together with viruses from Indonesia isolated between 2014 and 2021 and a single 2020 Indian isolate. Pathogenicity testing using the intracerebral pathogenicity index in day-old chickens and mean embryo death time in embryonating chicken eggs revealed that the Bangladeshi isolates are velogenic. Inoculation of 35-day-old chickens with two NDV isolates (LT67 and N5) resulted in 100% morbidity by 3 days post inoculation (DPI), and all birds succumbed to infection by 7 DPI. Massive hemorrhages, congestion and necrotic lesions were observed in different visceral organs, which were typical for infection with a velogenic viscerotropic pathotype of NDV. At microscopic examination, tracheitis, severe pneumonia, focal proventriculitis, transmural enteritis, focal myocarditis, severe congestion and necrosis in kidneys, and lymphoid depletion in lymphoid tissues were found. Our study reports the first outbreak of the panzootic genotype VII.2 NDV in poultry in Bangladesh and documents a possible recent re-introduction of this NDV genotype from Southeast or East Asia. This study further provides viral distribution and epidemiological data that can facilitate the effective control of NDV.     

Avian Hepatitis E Virus in Chickens,Taiwan, 2013

A previously unidentified strain of avian hepatitis E virus (aHEV) is now endemic among chickens in Taiwan. Analysis showed that the virus is 81.5%–86.5% similar to other aHEVs. In Taiwan, aHEV infection has been reported in chickens without aHEV exposure, suggesting transmission from asymptomatic cases or repeated introduction through an unknown common source(s).     

Experimental infection of chickens with Histomonas meleagridis confirms the presence of antibodies in different parts of the intestine

Specific pathogen-free chickens were infected with a clonal culture of the protozoan parasite, Histomonas meleagridis. Severe lesions were found within the caeca of all birds euthanized at 7 and 14 days post-infection (d.p.i.). Following necropsy of birds, intestinal samples were taken to establish ex vivo tissue cultures to determine the IgG, IgA and IgM antibody levels in the supernatants before and after incubation with a recently established ELISA. Presence of antibodies was also determined in the sera and first optical density values for IgG above the cut-off were detected at 14 d.p.i. IgA levels remained low in the serum with a small peak 4 weeks p.i., a phenomenon also found for IgM. The intestinal tissue samples showed very strong immunological reactions in the parasitized caeca with an initial peak of IgM, high levels of IgG and a continuous increase of IgA. In the duodena and jejuna, IgA values reached similar high levels as those obtained in the caeca, whereas IgG and IgM increased only slightly.     

生物与非生物性腱鞘代用品预防屈肌腱粘连作用效果比较的实验研究

目的:以生物膜与金箔为代表,观察生物与非生物性腱鞘代用品预防屈肌腱粘连的作用机制及效果,并加以比较,为临床应用提供可靠的理论及实验依据。方法:应用鸡趾屈肌腱横断修复模型,不同时间取材,通过生物力学、大体观察、组织学及电镜检查,观察肌腱愈合情况、粘连形成情况及假鞘结构。结果:生物膜与金箔组肌腱均为内源性愈合,并形成具有正常滑膜A、B型细胞的假鞘结构,与肌腱间有间隙。结论:(1)生物膜与金箔防粘连作用机制相似,都是通过形成假鞘来发挥作用,作用效果无明显差异。(2) 用具有良好组织相容性的物质将肌腱与周围组织分隔,将有效地防止肌腱粘连,从而提高肌腱的滑动功能     

Low Pathogenicity H7N3 Avian Influenza Viruses Have Higher Within-Host Genetic Diversity Than a Closely Related High Pathogenicity H7N3 Virus in Infected Turkeys and Chickens

Within-host viral diversity offers a view into the early stages of viral evolution occurring after a virus infects a host. In recent years, advances in deep sequencing have allowed for routine identification of low-frequency variants, which are important sources of viral genetic diversity and can potentially emerge as a major virus population under certain conditions. We examined within-host viral diversity in turkeys and chickens experimentally infected with closely related H7N3 avian influenza viruses (AIVs), specifically one high pathogenicity AIV (HPAIV) and two low pathogenicity AIV (LPAIVs) with different neuraminidase protein stalk lengths. Consistent with the high mutation rates of AIVs, an abundance of intra-host single nucleotide variants (iSNVs) at low frequencies of 2–10% was observed in all samples collected. Furthermore, a small number of common iSNVs were observed between turkeys and chickens, and between directly inoculated and contact-exposed birds. Notably, the LPAIVs have significantly higher iSNV diversities and frequencies of nonsynonymous changes than the HPAIV in both turkeys and chickens. These findings highlight the dynamics of AIV populations within hosts and the potential impact of genetic changes, including mutations in the hemagglutinin gene that confers the high pathogenicity pathotype, on AIV virus populations and evolution.     

Rapid development and evaluation of a live-attenuated QX-like infectious bronchitis virus vaccine

Infectious bronchitis (IB) is an acute, highly contagious disease, which causes economic losses to the poultry industry worldwide. To control the disease, biosecurity and vaccination are required. In the current research, we rapidly attenuated a QX-like IBV field strain ZYY-2014 using passage in embryos at limiting dilution and tested the safety and efficacy of the attenuated Chinese QX-like IBV strain ZYYR-2014 in 1-day-old specific-pathogen-free (SPF) chickens through spray route. Our result revealed that the attenuated strain presented a decreased pathogenicity in 1-day-old chickens. The strain ZYY-2014 inoculated birds presented typical IBV clinical signs with a mortality of 43%, while the attenuated strain ZYYR-2014 inoculated birds remained healthy. The strain ZYYR-2014 also presented stronger antibody responses and lower viral loads in tracheas, lungs and kidneys. When vaccinated through spray route into 1-day-old SPF chickens, our data suggest a potential of the attenuated ZYYR-2014 strain as a vaccine candidate applied in hatchery, which can contribute in preventing the QX-like IBV infections. Furthermore, attenuation by passage at limiting dilution could be applied for rapid vaccine development against emerging strains.     

鲜蛆替代国产鱼粉对海兰棕壳蛋鸡产蛋性能的影响

目的：观察猪粪饲养的蝇蛆替代国产鱼粉作饲料对海兰棕壳蛋鸡产蛋性能的影响。方法：用猪粪饲养蝇蛆，收集3龄鲜蛆直接替代国产鱼粉饲养40周龄海兰棕壳蛋鸡，设不同量鲜蛆替代组和鱼粉对照组，观察蛋鸡的日平均产蛋率、日平均产蛋量和平均蛋重，记录饲料消耗量和蛋鸡死亡数，用SPSS统计软件分析结果。结果：用鲜蛆蛋白半量替代饲养蛋鸡，蛋鸡产蛋能力优于常量国产鱼粉蛋白饲养，用鲜蛆等量和低于半量鱼粉蛋白量饲养蛋鸡，能取昨与常量鱼粉蛋白相同的饲养效果。用猪粪饲养的鲜蛆直接饲养蛋鸡不会增加疫病的发生。结论：鲜蛆饲养海兰棕壳蛋鸡的产蛋性能优于国产鱼粉，可不经消毒直接饲养蛋鸡。